Abstract: For aluminum disks and glass-made hard disks, those disks having a mean waviness of less than 3 Å are being desired in order to increase the density of memory capacity. The present invention provides polishing compositions that can give smoothly polished surfaces for the disks. The polishing compositions are polishing compositions for aluminum disks or substrates having silica on the surface thereof, which contain colloidal silica particle groups having different particle size distributions and have a SiO2 concentration of 0.5 to 50% by weight.

Abstract: The present invention provides an abrasive compound suitable for polishing the surface of a glass substrate for an optical disk platter or a magnetic disk platter. More specifically, the present invention provides an abrasive compound for a glass hard disk platter, characterized as comprising a stable slurry having water and, dispersed therein as an abrasive, cerium(IV) oxide particles having an average secondary particle size of 0.1 to 0.5 &mgr;m and containing CeO2 in a concentration of 0.2 to 30 wt %. Preferably, the present invention provides the above abrasive compound in which cerium amounts for 95% or more in terms of oxides of the total amount of rare earth elements in the abrasive.

Abstract: Substantially monodisperse crystalline ceric oxide sols and processes for producing such sols are provided. Sols include crystalline ceric oxide particles having a particle size I (particle size converted from specific surface area by gas absorption method) ranging from 10 nm to 200 nm and a ratio of particle size II (particle size measured by dynamic light scattering method) to particle size I ranging from 2 to 6. Sols can be prepared by reacting a cerium (III) salt with an alkaline substance in an aqueous medium under an inert gas atmosphere to obtain a suspension of cerium (III) hydroxide, immediately blowing oxygen or a gas containing oxygen into the suspension to obtain a sol comprising crystalline ceric oxide particles, and wet grinding the resulting sol. Sols are also prepared by calcining cerium carbonate at a temperature of 300 to 1100° C. to give cerium oxide particles, and wet-grinding the resulting particles.

Abstract: For aluminum disks and glass-made hard disks, those disks having a mean waviness of less than 3 Å are being desired in order to increase the density of memory capacity. The present invention provides polishing compositions that can give smoothly polished surfaces for the disks.

Abstract: An up-converter section and a down-converter section are contained in separate respective chassis. The up-converter section and the down-converter section are linked by an IF link section having a coaxial shielding structure. As such, a high-quality Up/Down tuner can be provided which is able to reduce the mutual influence of up-converter and down-converter local oscillator circuits and the entry of external noise, without increasing the size of the Up/Down tuner.

Abstract: There is provided a crystalline ceric oxide sol that is approximately monodisperse, and a process for producing the sol.

Abstract: Production of an alumina powder characterized by having a single or multiple crystal structure selected from the group consisting of &ggr;, &dgr; and &thgr;-forms, a primary particle size of 10 to 50 nm, a mean secondary particle size of 100 to 500 nm, and a granular primary particle shape, or an alumina powder characterized by having an a-form crystal structure, a primary particle size of 60 to 150 nm, a mean secondary particle size of 200 to 500 nm, and a granular primary particle shape, using as a raw material an alumina hydrate comprising rectangular plate-like primary particles having a boehmite structure and having a length of one side of 10 to 50 nm; and preparation of a polishing composition comprising the alumina powder, water and a polishing accelerator.

Abstract: There is provided an abrasive used for polishing a substrate which comprises silica as a main component, for example a rock crystal, a quartz glass for photomask, for CMP of an organic film, Inter Layer Dielectric (ILD) and shallow trench isolation of a semiconductor device, or for polishing a hard disk made of glass.

Abstract: The present invention relates to a polishing composition for polishing alumina disks, polishing substrates having silica surfaces and semiconductor wafers, comprising a stable aqueous silica sol containing moniliform colloidal silica particles having a ratio (D1/D2) of a particle diameter D1 nm (as measured by dynamic light scattering method) to a mean particle diameter D2 (as measured by nitrogen absorption method) of 3 or more, wherein D1 is between 50 to 800 nm and D2 is between 10 to 120 nm, said moniliform colloidal silica particles being composed of spherical colloidal silica particles and a metal oxide-containing silica bond which bonds these spherical colloidal silica particles together, wherein the spherical colloidal silica particles are linked together in rows in only one plane by observation through an electron microscope, and further wherein said polishing composition contains 0.5 to 50% by weight of said moniliform colloidal silica particles.

Abstract: According to the present invention, a process is provided for producing crystalline ceric oxide particles having a particle diameter of 0.005 to 5 &mgr;m, which comprises the steps of reacting a cerium (III) salt with an alkaline substance in an (OH)/(Ce3+) molar ratio of 3 to 30 in an aqueous medium in an inert gas atmosphere to produce a suspension of cerium (III) hydroxide, and blowing oxygen or a gas containing oxygen into the suspension at a temperature of 10 to 95° C. and at an atmospheric pressure.

Abstract: A polishing composition for an aluminum disk includes water, an alumina abrasive agent and a polishing accelerator. The polishing accelerator is preferably basic aluminum nitrate. A process for polishing an aluminum disk using the polishing composition is also provided.

Abstract: According to the present invention, a process is provided for producing crystalline ceric oxide particles having a particle diameter of 0.005 to 5 .mu.m, which comprises the steps of reacting a cerium (III) salt with an alkaline substance in an (OH)/(Ce.sup.3+) molar ratio of 3 to 30 in an aqueous medium in an inert gas atmosphere to produce a suspension of cerium (III) hydroxide, and blowing oxygen or a gas containing oxygen into the suspension at a temperature of 10 to 95.degree. C. and at an atmospheric pressure.

Abstract: A liquid crystal display is constructed such that a black resin film is formed on the wiring region outside of the sealing compound that seals the liquid crystal between opposed substrates. This results in preventing corrosion of the leading fine wire between an OLB electrode and a pixel on the liquid crystal display panel and thereby prevents breaking of wires formed on the array substrate on the outside of the sealing compound and short-circuiting between the wires. The black resin film forms an excellent protective layer in place of the conventional silicon resin coating step designed for this purpose.

Abstract: The present invention is to provide a process for preparing ceric oxide particles used as an abrasive or polishing material for producing semiconductors or as a UV ray-absorbing material for plastics, glass and the like.The present invention relates to a process for preparing cerium (IV) oxide particles having a particle size of from 0.03 .mu.m to 5 .mu.m, which comprises adjusting an aqueous medium containing cerium (IV) hydroxide and a nitrate to a pH of from 8 to 11 with an alkaline substance and heating the aqueous medium at a temperature of from 100.degree. to 200.degree. C. under pressure.